1. OPCATeam OPM-based Collaborative Systems Modeling
BPM 2004
Dov Dori, Dizza Beimel, Eran Toch
Technion, Israel Institute of Technology

2. Agenda: OPM Overview OPCATeam Project Goals Problem Specification
OPCATeam Architecture
Implementation
Summary and Future Work

3. What is OPM - Object-Process Methodology?
A comprehensive paradigm for
modeling
engineering
lifecycle support
of complex, multi-disciplinary systems

4. OPM’s Building Blocks are Things: Objects and Processes

5. Objects and Processes
Objects and processes are two types of equally important things (entities) required to describe a system in a single, unifying model
At any point in time, each object is at some state
Object states are transformed through the occurrence of a process

6. A process changes an object state

7. A process generates a new object

8. OPM has a single model with a bimodal representation
A single diagram type: Object-Process Diagram (OPD)
A corresponding subset of language:
Object-Process Language (OPL)

9. Resources: OPM book Dov Dori
Object-Process Methodology - A Holistic Systems Paradigm,
Springer Verlag, Berlin, Heidelberg, New York, 2002

10. Resources: OPM Website www.ObjectProcess.org
Free OPCAT downloads
Publications

11. OPCAT – Object-Process CASE Tool – single user version
Serves one user at a time
The data and metadata of each model is saved in an XML file.
The program reads the information from the XML file, while building its internal Data Structures.
The main Data Structure is Hash Table.

12. What is Collaboration ?
“To work jointly with others or together, especially in an intellectual endeavor.” [Webster]
Collaboration is associated with groupware technology, which is designed to facilitate the work of groups.
IBM Lotus Notes NetMeeting
Documentum CVS
TeamSCOPE

13. Project goal & Objectives
Goal: Specify and implement a collaborative environment, where teams of modelers collaborate in OPM-based analysis, design, and implementation of systems
Objectives:
Support concurrency, communication, security
Use OPCAT as the basis for OPCATeam
Employ Web technologies

14. Objectives attainment guidelines
Concurrency:
The model should be available to all the members enabling them to get the most up-to-date view.
Developers work on the same shared system at the same time, based on a single consistent model that describes it.
Communication:
Team members should be able to communicate freely regardless of their physical whereabouts.
Security:
The model under construction should be protected from unauthorized external access and changes by unauthorized modelers.

15. Two conflicting requirements
Enabling independent, parallel work on a distributed OPM model
Keeping the model integrity

16. Problem: OPM interconnectivity
OPDs in the OPD set are interconnected.
OPDs can share common entities (objects, processes or states), each change in a common entity potentially influences other OPDs.

17. Problem Example
Modeler A
Modeler B SD ≠?
SD1
SD2

18. OPCATeam Architecture

19. Security Three access permission levels: The diagram permissions
workgroup
OPM model
diagram.
The diagram permissions
Reduce the number of conflicts between concurrent updates
Prevent designers from affecting shared elements while allowing them to refine these elements.

20. The Model Manager Handles concurrent development of OPM models
Uses a central repository and a concurrent update mechanism.
Allows simultaneous user updates to a single OPM model
Includes a version control function that logs updates and enables revision control.

21. Access Control Workgroup access level OPM model access level
Admin
Create OPM model
View workgroup
OPM model access level
Commit model
View OPM mode
OPD access level
Edit OPD
Refine OPD
view OPD

22. Access Control example (1)

23. Access Control example (2)

24. The OPCATeam Client Identical with the single-user OPCAT :
Supports OPM
Visually
Textually
Logically
Interface to collaboration utilities:
Server communication
Chat
Presence window
Runs the access control mechanism.

25. Implementation Overview

26. Server: Collaborative Session
Users can create Collaborative Session on a model according to their permissions.
A user can participate in one session at a time.
Users can collaborate by sharing the same session.
Sharing is enabled by giving permission
A session has a “Token Holder” - the current model editor.
The token is passed between the authorized session participants.
The session can be committed only by a team member that holds committing authorization.
The session data and metadata is saved on the server.

27. Server: Administration
Local administration
Create/Update/Disable workgroups,models,sessions.
Handle the session: login, save, commit
Global administration
Handled through a web interface.
Disable/Enable/Update/Delete workgroups, users, models, sessions
Provide statistics.

28. Server: Version Control
Provide basic version control functionality:
Get latest version
Check out file
Check in file
Get file status
File can be checked out by one or more users.
Once file had been checked in, it gets a new version number.
The date and author are saved.
The current implementation uses built-in version control module.

29. Technologies JBoss J2EE Application Server
AXIS Web Services Implementation
Using the SOAP protocol
JMS – Java Message Service
MySQL/InnoDB

30. New Collaboration Products
Poseidon for UML has announced a new product “Enterprise Edition: UML in Teams“ in March 2004
Collaboration on models.
The team is synchronized in real time.
Multi-user interaction.
Version control.
Rational Rose and Rhapsody base their collaborative features on standard version control software. Concurrency is achieved by breaking the modules into separate files.
This type of solution does not suit OPM, because of the strong connections between the diagrams.

31. Comparison Chart OPCATeam Poseidon Rhapsody Architecture Client-Server
Stand Alone version
Concurrent development
restricted merge utility
----
Strong diffmerge utility
Permissions mechanism
Robust mechanism, define specific model levels
Restricted: built on top of NetMeeting, CM tool
CM support
Built In Revision Control.
Support CVS
Support CVS (through the admin utility)
Supports most of the leading CM products
Administration
Web Admin, secured.
Client Admin , not secured.
Collaboration:
1.File updated
2.Presence window
3.Chat
4.Session Concept
Through Token- time restricted editor at a time.
Built In
persistent
Online sync, locks can be taken for ever.
Restricted- only lockers
Restricted: non persistent
Based on NetMeeting:
User has to request the editing permission.
Manually, not model-based
Restricted- no sys msgs.

32. Summary OPCATeam implementation follows the guidelines:
Concurrent work is achieved through a collaborative session and a merge utility
Security is achieved through the access control mechanism
Communication is achieved through the collaborative session, chat room, and presence window.

33. Future work Collaborative aspects: Concurrency aspect: Web aspect:
Implement OPD permission level
Implement execution stack on the server (replace the token mechanism, allows semi-concurrent updates)
Concurrency aspect:
Improve the merge utility
Web aspect:
Create a user portal (today only admin portal supported)
Near future tasks:
Port the code from JBoss to IBM WebSphere.
Define groups , each user has to be part of one or more groups
Support GUID and transactions managing
investigate native security aspects in J2EE